----- Original Message ----- From: "Greg Rosenstock" <greg@bluefeather.ie> To: "'Astronomy Ireland'" <info@astronomy.ie> Sent: Wednesday, July 16, 2003 2:19 PM Subject: RE: [Astronomy Ireland] Mars+Moon; Celestron's NEW SkyMaster binoculars (and VistaPix)
Thanks for the reminder, David! At the risk of sounding stupid, how would the 20 x 100 binoculars compare in magnification and effectiveness to, say, the Celestron Firstscope 70? All the best,
Binoculars and telescopes are a bit like cars and motorbikes in that both cars and motorbikes are used for transport but they have obvious advantages and disadvantages! With binos and scopes the pros and cons are not as obvious to the beginner so I thought I'd CC this message to everyone on the AI emailing list, though this will be the last such message on this subject as we don't want to clutter the list with too much correspondence on one particular subject. Binoculars and telescopes are really separate entities. Binos are dead handy to just grab and use. They have a wide field of view and are great for deep-sky use, watching planets close to the Moon (eg tonight!) etc. Telescopes give much closer views and will show much more detail on bright objects like planets, the Moon, double stars, etc. even if they don't collect as much light as a given pair of binos. Some objects look great in binos and useless in telescopes e.g. Pleiades, Beehive star cluster, Andromeda Galaxy are better seen in big binoculars than in big telescopes, and vice versa - you'll see no detail on Jupiter or Mars even with 25x100s. So you really have to get both if you want the best of both worlds. To answer your specific question. 25x100s have two 100mm lenses and therefore collect the same amount of light as a 142mm lens (close to our CR150-HD 6-inch refractor!) So big deep sky objects that do not need more than 25x magnification will be better in the 25x100mm binoculars than the FS70EQ. I have seen detail on the surface of Mars in 2001 using the FS70EQ but the 25x100s will NOT show any detail on Mars, 25x is just too low magnification. So you have a difficult choice, get a great pair of binos and rule out planetary surface detail viewing for the time being, or go for the scope and suffer a little in the deep sky department. Of course, once you get one of the two instruments you can immediately start saving for the other! You should own both a good quality scope and at least one good pair of binoculars. If you have the budget get both, if not together, then within a short period of one another. Hope that answers your query. Don't forget the Moon and Mars tonight! P.S. If you haven't booked your Star-B-Q tickets yet for August 22 and you intend coming then I would do so very soon, about two thirds are already sold and I'm beginning to wonder if we'll have any of the 200 left by the end of the week, which is a good complaint! See http://www.astronomy.ie/sbq.html and the booking form at http://www.astronomy.ie/sbqform.rtf or just call. ===== David Moore BSc FRAS, Chairman, Astronomy Ireland, P.O.Box 2888, Dublin 5. Editor, "Astronomy & Space" magazine. ASTRONOMY SHOP: open Mon.-Fri. 9am-6pm and Sat. noon-6pm. Tel (01) 847 0777. Fax (01) 847 0771. WWW: http://www.astronomy.ie (Subscribe FREE to AI's Events emailing list) Email: info@astronomy.ie